"Geothermal energy will play a key role in powering America's energy future," Kempthorne said, "and 90 percent of our nation's geothermal resources are found on federal lands."

The plan would identify about 118 million acres of public lands managed by the Bureau of Land Management and 79 million acres of National Forest Service lands for future geothermal leasing.

"Facilitating their leasing and development under environmentally sound regulations is crucial to supplying the secure, clean energy American homes and businesses need," the secretary said in Phoenix where he has been attending the annual convention of the National Congress of American Indians.

There are 29 geothermal power plants currently operating on Bureau of Land Management lands in California, Nevada and Utah, with a total generating capacity of 1,250 megawatts, enough to supply the electricity needs of 1.2 million homes.

The largest group of geothermal power plants in the world is located in The Geysers, a geothermal field in California. Currently, geothermal power supplies less than one percent of the world's energy.

Under the plan announced today, known as the Final Geothermal Programmatic Environmental Impact Statement, 5,540 megawatts of new electric generation capacity from geothermal resources could be in place by 2015.

One megawatt of geothermal energy powers more than 1,000 homes, so if the newly announced plan is implemented, new geothermal energy could meet the needs of 5.5 million homes.

In addition, the plan estimates an additional 6,600 megawatts by 2025 for a total of 12,100 megawatts - enough to power more than 12 million homes.

Kempthorne points to growing interest in developing these resources shown by the results of recent Bureau of Land Management geothermal lease sales in areas where current Resource Management Plans already allow geothermal development.

An August 2007 sale drew the highest ever per-acre bid for a lease in The Geysers field. And a sale of leases in Nevada brought a record-breaking $28.2 million in August 2008.

Kempthorne noted the strong interest states, local communities, industry and environmental groups took in the development of this plan.

"This process has benefited greatly from the involvement of both governmental and nongovernmental stakeholders, and from the clear direction Congress gave in the 2005 Energy Policy Act," the secretary said.

Geothermal resources range from heat found just under the ground to hot water and rock miles below the Earth's surface. Wells over a mile deep can be drilled into underground reservoirs to tap steam and very hot water that can be brought to the surface to generate electricity.

There are environmental concerns around geothermal energy. Dry steam and flash steam power plants emit low levels of carbon dioxide, nitric oxide, and sulphur, although at roughly five percent of the levels emitted by fossil fuel power plants.

To resolve these concerns, geothermal plants can be built with systems that can inject these substances back into the Earth, reducing carbon emissions to less than 0.1 percent of those from fossil fuel power plants.

Hot water from geothermal sources will contain trace amounts of toxics such as mercury and arsenic, which if discharged into rivers can make the water unsafe to drink.

To protect special resource values, the plan announced today identifies a comprehensive list of stipulations, conditions of approval and best management practices required for approval of future geothermal leases.

Lands closed to geothermal leasing will remain closed. Lands within a unit of the National Park System, such as Yellowstone National Park, for instance,will continue to be unavailable for leasing. The plan also excludes wilderness areas and wilderness study areas from geothermal development.

It will allow discretionary closure of Areas of Critical Environmental Concern where the BLM determines that this is appropriate. The BLM may also implement discretionary closures of units of the National Landscape Conservation System.

The Forest Service will use information in the plan to facilitate leasing analysis to determine whether or not geothermal leasing is appropriate and to evaluate its land use plans and amend them as needed through a separate environmental review process.

These leases were filed before January 1, 2005 for specific lands in Alaska, California, Nevada, Oregon and Washington managed by the Forest Service or the Bureau of Land Management. Decisions on these 19 leases could proceed as soon as the Record of Decision is signed on the Final Geothermal Programmatic Environmental Impact Statement.

The Bureau of Land Management and the U.S. Forest Service will publish the final version of the plan in the Federal Register on Friday, October 24, 2008. It will be available online at http://www.blm.gov/Geothermal_EIS.

The governors of the 12 states in the plan's project area each will have the opportunity to review the final document to ensure consistency with state plans, programs, and policies.

The Bureau of Land Management will wait until the end of the Governor's consistency review period before signing and issuing the Record of Decision approving the land use plan amendments. Kempthorne says any inconsistencies will be resolved before a Record of Decision is issued.